Amphibian

ABSTRACT

The present invention provides, with reference to FIG.  2,  an amphibian operable in land and marine modes, the amphibian comprising a hull, at least one discontinuity (wheel bay) provided in the hull, and at least one retractable wheel or track assembly at least partially located in the at least one discontinuity (wheel bay). The hull is a planing hull, and the at least one discontinuity (wheel bay) is provided in the front half of the hull of the amphibian. The amphibian further comprises at least one conduit which opens, or is provided with an entry which opens, into or at the at least one discontinuity (wheel bay) and is configured for channelling, in use, fluid away from the at least one discontinuity (wheel bay).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/130,210, filed on Aug. 27, 2014, entitled “AMPHIBIAN,” which claimsthe benefit of International Application No. PCT/GB2012/051550, filed onJul. 2, 2012, entitled “AMPHIBIAN,” the entire disclosures of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to an amphibian and, in particular, to ahigh speed amphibian with a hull form configured with a single frontwheel or track station, and/or for receiving single front wheel ortrack.

Amphibians for recreation, business, and/or military uses are known. Inthe past, designers of amphibians have focussed their efforts onoptimising either on-water or on-land performance. As a result, eitheron-water performance has been sacrificed in order to give satisfactoryon-land performance, or on-land performance sacrificed to givesatisfactory on-water performance. The resulting amphibians arecompromised to one degree or another.

To enable an amphibian to attain greater speed on water, it is desirablefor the amphibian to be provided with a planing hull. Such a hull can bepowered from standing where it is fully displaced to a speed where itcan generate sufficient hydrodynamic lift to rise up out of the waterand plane across the surface of the water. It is known for suchamphibians to have a retractable wheel assembly that enables the wheelsof the amphibian to be raised to a retracted position during use of theamphibian on the water. In addition, a hull provides buoyancy to theamphibian such that it floats while in the water.

Generally, for optimal performance, the surface of a planing hull shouldcontain as few discontinuities as possible, as disruptions to thesurface of the hull will increase drag and compromise both thehydrodynamic lift achievable and handling on water. However, the natureof an amphibian is such that it can require the surface of the hull tocontain discontinuities, such as recesses within which components, forexample wheel and suspension assemblies, are located. When attempting tooptimise on-water performance, designers of amphibians with retractablewheel and suspension assemblies have expended great effort in providingmovable cover mechanisms for wheel arch cut outs to re-establish thesmooth uninterrupted lines of a conventional marine hull when the wheelsare retracted. Movable covers and plates are known in amphibians forexample from United States patents U.S. Pat. No. 4,958,584 (Williamson),U.S. Pat. No. 3,421,472 (Oberg), and U.S. Pat. No. 3,280,785 (Oberg).The sliding and/or hinging mechanisms of movable covers or plates areliable to seize up through corrosion, and/or through ingress of mud,sand, silt, salt, or other marine debris. They may also be damagedthrough collision with objects such as rocks during vehicle modeconversion or off-road use. An amphibian which cannot change mode may beimmobilized; either on land, or even worse, on water. Furthermore, thenecessity of maintaining and scrupulously cleaning sliding and/orhinging mechanisms may not likely be acceptable to the vehicle owner,who will be accustomed to the less onerous demands of modern cars andboats. Although movable covers or plates have been proposed in severalamphibians patents as noted above, these have not made it to seriesproduction.

In addressing the above problems in the more recent past, the applicanthas retained wheel arches in the hull but developed hydrodynamic aidssuch as planing plates to help recover at least part of the hull form(as disclosed in the applicant's UK Patent No. GB2401832B) and strakesto improve directional stability of the hull when on the plane (asdisclosed in the applicant's UK Patent No. GB2401833B).

Hulls for amphibians comprising three or more wheels, at least two ofwhich are provided at the front of the amphibian, typically providesufficient buoyancy on water since the width of the amphibian, and thusthe hull, span the width of the front and/or rear axle plus wheels.However, an amphibian having just one front wheel or wheel stationpresents unique challenges with respect to the hull shape, size,displacement etc., since the amphibian can be required to lean sidewaysduring riding/turning on land, thereby requiring a hull with arelatively narrow width at least at the front, yet the hull must providesufficient buoyancy to keep the amphibian afloat in the water. Prior artamphibian motorcycles have attempted to meet these challenges usingadditional movable flotation elements that extend from the hull whilethe amphibian is in the water. These movable flotation elements may takethe form of inflatable bellows, movable or foldable flotation aids, orother forms. Such systems have been bulky, required additional movingparts/components, and can be prone to failure. As such, an amphibianmotorcycle with a hull that does not require additional bellows,provides sufficient buoyancy for the amphibian to float in the water,and yet allows the amphibian to adequately lean/turn while on land wouldbe desirable.

SUMMARY OF THE INVENTION

The applicant has developed a high speed amphibian with a single frontwheel or track station, and/or single front wheel or track. Theamphibian may comprise one or more rear wheel or track stations, and/orone or more rear wheels or tracks. Accordingly, the high speed amphibianmay take the form of a motorcycle, tricycle or other configurationhaving a single front wheel or track station, and/or single front wheelor track. The amphibian need not be a motorcycle or tricycle (i.e. isnot limited to an amphibian having handlebars for steering and/or sitastride seating). Alternatively, for example, the amphibian may take theform of a sit in vehicle or buggy. The amphibian can plane on water, yethas on-road, off-road and utilitarian capability. Surprisingly, this newamphibian capability has been achieved without using additional movableflotation elements that extend from the hull while the amphibian is inthe water. To this end, the applicant has gone against conventionalthinking and overcome previous technical prejudices in arriving at theconfiguration according to the present invention.

In particular, the applicant has developed the shape and configurationof the front bow section of the hull of the amphibian to include one ormore conduits for channelling water in order to arrive at an optimisedhull form for high speed amphibian use and which provides sufficientbuoyancy. The optimised hull form retains an exposed frontal wheel baywhich, without the conduit(s) of the present invention, suffered fromaccumulations of water resulting from forward motion of the amphibian.These water accumulations in the frontal wheel bay gave rise tosignificant spray and inefficiencies in pushing this accumulated waterforwards. The optimised hull form provides for improved hydrodynamicperformance of the amphibian when on water as the accumulation of waterin the front wheel bay resulting from forward motion of the amphibiancan travel along the or each conduit as well as or in place of having topass under the bow portion of hull portion and on under the hull.Furthermore, the hull form is also optimised for land use of theamphibian.

Accordingly, the present invention provides, in a first aspect, anamphibian operable in land and marine modes, the amphibian comprising:

a hull;

at least one discontinuity provided in, or formed by, the hull; and

at least one retractable wheel or track assembly at least partiallylocated in the at least one discontinuity, wherein:

the hull is a planing hull;

the at least one discontinuity is provided in the front half of the hullof the amphibian; and

the amphibian further comprises at least one conduit which opens, or isprovided with an entry which opens, into or at the at least onediscontinuity and is configured for channelling, in use, fluid away fromthe at least one discontinuity.

In a second aspect, the present invention provides an amphibian operablein land and marine modes, the amphibian comprising:

a hull;

at least one wheel or track bay provided in, or formed by, the hull; and

at least one retractable wheel or track assembly at least partiallylocated in the at least one wheel or track bay, wherein:

the hull is a planing hull;

the at least one wheel or track bay is provided in the front half of thehull of the amphibian; and

the amphibian further comprises at least one conduit which opens, or isprovided with an entry which opens, into or at the at least one wheel ortrack bay and is configured for channelling, in use, fluid away from theat least one wheel or track bay.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will now be described byway of example only with reference to the accompanying drawings, inwhich:

FIG. 1 is a schematic top plan view of an amphibian motorcycle accordingto a first preferred embodiment of the present invention;

FIG. 2 is a schematic bottom plan view of the amphibian of FIG. 1;

FIG. 3 is a schematic side elevation view of the amphibian of FIG. 1illustrating indicatively the front wheel and the rear wheel in aprotracted position and in a retracted position (in phantom);

FIG. 4 is a schematic bottom plan view of a three wheel amphibianaccording to a further preferred embodiment of the present invention;

FIG. 5 is a detailed schematic bottom plan view of a frontal bow sectionof an amphibian according to a further preferred embodiment of thepresent invention;

FIG. 6 is an enlarged detailed schematic view from below and to one sideof the frontal bow section of FIG. 5;

FIG. 7 is a schematic bottom plan view of a two wheel amphibianaccording to a further preferred embodiment of the present invention;and

FIG. 8 is a schematic bottom plan view of a three wheel amphibianaccording to a further preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to FIGS. 1 to 3, a first preferred embodiment of thepresent invention can be seen to comprise an amphibian motorcycle 10that has desirable leaning and/or turning capability while in use on theland and desirable buoyancy and stability while in use on water. It willbe appreciated that for the purposes of the present invention, the termmotorcycle includes mopeds, scooters and other single-track two-wheeledvehicles. In addition, other single-track vehicles that use more thanone wheel or track as a front wheel and/or rear wheel are includedwithin the term motorcycle. For example, and for illustrative purposesonly, a scooter that has two wheels spaced closely together for use asthe front and/or rear wheel is included within the use of the termmotorcycle herein. In this case, there is a front wheel station and arear wheel station, with one or more wheels or tracks provided in eachwheel station.

The amphibian 10 can be seen to comprise a front wheel 110, preferablyprovided with a front suspension system (not shown), and a rear wheel120, again preferably provided with a rear suspension system (notshown). A track or tracks may be used as an alternative to either orboth of the front and rear wheels 110, 120. At least one wheelretraction system (not shown) that is operable to move the front wheel110 and/or the rear wheel 120 between a protracted position for use ofthe amphibian 10 on land and a retracted position for use of theamphibian 10 on water is preferably included. The front wheel 110 and/orthe rear wheel 120 can then be moved between a protracted position, foruse of the amphibian 10 on land (including entry into and egress fromthe water), and a retracted position for use of the amphibian on water.The front wheel 110 and/or the rear wheel 120 may moved into theretracted position to reduce drag when the amphibian 10 is operated inwater. The amphibian 10 is provided with a hull 200 with a centreportion 210 and two oppositely disposed and spaced apart side portions220. Alternative hull configurations are possible. Each hull portion210, 220 has a forward end defining a bow or bow portion 212, 222 andthe hull portions 210, 220 are preferably fixed relative to one anotherand form a generally rigid assembly with a generally continuous outerhull surface. The two side portions 220 extend forwardly beyond thecentre portion 210 a predefined distance and form a front wheel bay 116.The front wheel 110 can be located at least partially within the frontwheel bay 116 and the two side portions 220 can extend forwardly beyonda rotation axis 111 of the front wheel 110 when in the protracted landengaging position, although this is not essential. In some instances,the two side portions 220 can stop short of the rotation axis 111 of thefront wheel 110, or can extend at least partially or generally up to orequal to a front surface of the front wheel 110. In the alternative, thetwo side portions 220 can extend beyond the front surface of the frontwheel 110 when the front wheel 110 is in the protracted position. Thetwo side portions 220 can also extend rearwardly beyond the centreportion 210 a predefined distance and form a rear wheel bay 126. Therear wheel 120 can be located at least partially within the rear wheelbay 126 and the two side portions 220 can extend rearwardly up to, orbeyond, a rotation axis 122 of the rear wheel 120 when in the protractedposition. In some instances, the two side portions 220 can extendrearwardly at least partially or generally up to or equal to a rearsurface of the rear wheel 120 or, in the alternative, the two sideportions 220 can extend rearwardly beyond the rear surface of the rearwheel 120 when the rear wheel 120 is in the protracted position.

A conduit 214 is provided in one or both of the two side portions 220 soas to provide at least one pathway between the front wheel bay 116 therespective lateral side or sides of the amphibian 10 for fluids (waterand/or air) to pass. The or each conduit 214 may take any suitable form.For example, the conduit 214 may be open on the underside in the form ofa channel, or may be at least partially closed (across and/or lengthwaysof the conduit 214) by the hull 200 or other part of the amphibian 10 soas to form a tunnel. Indeed, the conduit 214 may take the form of a tube(e.g. a discrete part or formed by other parts of the amphibian 10). Thecross section of the conduit 214 may be substantially uniform, or mayvary along its length. More particularly, the cross section of theconduit 214 may reduce along its length in the rearward direction 2.Alternatively, the cross section of the conduit 214 may increase alongits length in the rearward direction 2. The entry 215 to the conduit 214may be integrated with either one or more of the bow or bow portions212, 222 of the hull portions 210, 220 or may be a discrete entry (suchas with a discrete tube). Preferably, the entry 215 to the conduit 214is open at and/or to the front wheel bay 116. The exit 216 from theconduit 214 may be an exit (discrete or otherwise) laterally to the sideof the amphibian 10, or may be integrated with either one or both of thehull portions 210, 220. Alternatively, the conduit 214 may continuealong a portion of, or the entire length of, the amphibian 10 exiting atthe rear stern or transom, or into and/or at a rear wheel bay 126. Theor each conduit 214 provides for improved hydrodynamic performance ofthe amphibian 10 when on water as the accumulation of water in the frontwheel bay 116 resulting from forward motion of the amphibian 10 cantravel along the or each conduit 214 as well as or in place of having topass under the bow portion 212 of hull portion 210 and on under the hull200. Further improved hydrodynamic performance of the amphibian 10 canbe achieved by shaping of the conduit, both in terms of its entry 215,exit 216, its path and its cross sectional area along its length. Forexample, by reducing the cross sectional area along the length of anopen channel form of conduit 214, water passing along is forced out ofthe conduit 214 along the open underside due to its incompressibility,thereby generating lift. In order for the amphibian 10 to make thetransition from its hull 200 being in displacement mode to one where itis planing, the through water speed of the amphibian 10 must beincreased to achieve the necessary hydrodynamic lift. The hull 200 andbow portions 212, 222 of the hull portions 210, 220 are key in reducingthe drag of the hull 10 and facilitating the necessary gain in speed ofthe amphibian through the water. Once on the plane, the hull 200provides directional stability. However, the hull 200 may besupplemented with conventional strakes or strakes as discussed in theapplicant's UK Patent No. GB2401833B.

With the two side portions 220 extending forwardly and/or rearwardlybeyond the centre portion 210 (as shown by way of example in theFigures), a hull with desirable flotation and minimum and/or desirablewidth is provided. Stated differently, extension of the side portions220 to form the front wheel bay 116 and/or the rear wheel bay 126provides desirable and/or adequate buoyancy for the amphibian 10 in thewater and yet affords for the amphibian 10 to desirably lean and/or turnduring use on the land.

With particular reference now to FIG. 1, the amphibian can be seen toinclude a motorcycle form 100 and a hull form 200. The motorcycle form100 can have a seat 130, handlebars 140, a prime mover (not shown), atransmission and/or speed change transmission (not shown) and othercomponents known to those skilled in the art that are used, attached,etc. with or to a motorcycle. For example, the rear wheel 120 can have arear mudguard 121, a drive chain, and the like. In addition, the frontwheel 110 can have a front mud guard (not shown), however this is notrequired. Alternatively or additionally, fenders or mud guards may befixed to the motorcycle form 100, hull form 200 or other part that doesnot move with the wheels 110, 120, at the front and/or the back.

Referring next to FIG. 2, the underside of the hull 200 can be seen indetail. The overall hull 200 is defined by the combination of the centreportion 210 and the side portions 220, which are preferably rigid withrespect to one another and together form a continuous outer hullsurface. The hull 200 may be said to have a bow at the forward end(direction 1) and a stern or transom at the rearward end (direction 2).The centre potion 210 has a forward end defining a centre bow 212 orcentre portion 212 of the bow. Each of the side portions 220 has aforward end defining a side bow 222 or a side portion 222 of the bow. Asused herein, a bow is the fowardmost end of the hull 200 or portion ofthe hull 200. In some instances, the side portions 220 can extend in aforwardly direction 1 beyond the centre portion 210 and create a frontwheel bay 116. In addition the two side portions 220 can extend in arearwardly direction 2 beyond the centre portion 210 and create a rearwheel bay 126. The front wheel 110 can be located at least partiallywithin the front wheel bay 116 and the rear wheel 120 can be located atleast partially within the rear wheel bay 126. The hull 200 can alsohave a waisted portion 204 that affords a rider of the amphibian 10 theability to place one or more feet on a ground surface in order tostabilize or hold the amphibian 10 in an upright position while in useon land when stopped. In addition, the hull 200 can have one or moreplatforms or sills 201 that afford for a rider to place their feet whileriding the amphibian 10 on land or water.

When on land, the amphibian 10 may be propelled by the rear wheel 120and/or front wheel 110 (or front or rear tracks where provided). When onwater, one or more jet drives or propellers or other marine propulsionmeans may be used. A pair of jet drives 230 and 232 are shown in FIG. 2.Each jet drive 230, 232 has respective inlet 234, 236 and respectiveoutlet 238, 240. The jet drive 230 is disposed at least partially in oneof the side portions 220 on one side of the rear wheel bay 126 and theother jet drive 232 is disposed at least partially in the other sideportion 220 on the opposite side of the rear wheel bay 126.Alternatively, a single jet drive or jet drive propulsion system (notshown) may be used. The single jet drive may have one or more inlets andone or more outlets, and be beneficially packaged as necessary. Forexample, the single jet drive may disposed centrally or at leastpartially in one of the side portions 220. The inlet(s) and outlet(s)may be positioned as necessary, e.g. with ducts to provide ducted flowaround or on one or both sides the rear wheel 120.

Referring next to FIG. 3, a side view of the embodiment shown in FIGS. 1and 2 is shown with the front wheel 110 and the rear wheel 120 in aprotracted position. It will be appreciated that with the front wheel110 and the rear wheel 120 in the protracted position, one can operatethe amphibian 10 on land as one would generally operate a motorcycle.FIG. 3 also illustrates in phantom the front wheel 110 and the rearwheel 120 in a retracted position such that the amphibian can beoperated at high speed, planing, on the water. An indicative water lineis shown at w, representing where the water line may be with theamphibian 10 in full displacement mode in the water and not moving. Ofcourse, the actual water line may vary from this position dependent uponthe specific parameters of the amphibian 10. It will be appreciated thatwith the two side portions 220 extending in the forwardly direction 1and/or in the rearwardly direction 2, the hull 200 provides a desirablebuoyancy for the amphibian 10 while maintaining a desirable and/orminimum width such that leaning and/or turning can be achieved while inuse on land. It will be further appreciated that at least one wheelretraction system can be included (not shown) in order to move the frontwheel 110 and/or the rear wheel 120 between the protracted position foruse of the amphibian 10 on land and the retracted position for use ofthe amphibian on water.

The front wheel bay 116 and/or the rear wheel bay 126 can have a cover,closure and the like across a top or upper portion thereof, however thisis not required. Such a top or upper cover or closure may be fixed inplace so as to form part of the upper, surface of the body or hull, maybe flexible, or may be operable. In contrast, the front wheel bay 116and the rear wheel 126 bay do not have a closure along a bottom or lowerportion thereof. This means that there is no closure or cover in theouter/lower surface of the hull 200. In this manner, the chance orthreat of a cover, closure and the like of being lost, broken,distorted, etc. during use is prevented. In addition, any malfunction ofsuch a cover, closure, etc. due to contamination by sand, mud, dirt,grass, etc. is also prevented. A closure is distinguished from a fenderor mud guard, which is permanently protracted whether the wheel isprotracted or retracted, and does not move from one position to anotherduring normal operation of the amphibian. Generally, a closure will belocated below the wheel when closed. A mud guard will often be fixed tothe body work and located above the wheel. When a mud guard is mountedon the forks supporting the wheel, it will be held in a fixedrelationship to the wheel. Its orientation may vary as the wheel isprotracted or retracted, however unlike a closure, it will not cover agap in the hull.

Referring next to FIG. 4, a further preferred embodiment of the presentinvention can be seen to comprise a three wheeled amphibian 10 that hasdesirable leaning and/or turning capability while in use on the land anddesirable buoyancy and stability while in use on water. It will beappreciated that for the purposes of the present invention, the terms“three wheel” or “tricycle” includes three wheel or tricycle mopeds,scooters and other three-wheeled vehicles. In addition, other vehiclesthat use more than one wheel or track as a front wheel and/or as one ormore of the rear wheels are included within the term three wheel ortricycle. Again, for example, and for illustrative purposes only, athree wheel or tricycle amphibian that has two wheels spaced closelytogether for use as the front and/or as one or more of the rear wheelsis included within the use of the term three wheel or tricycle herein.In this case, there is a front wheel station and two rear wheelstations, with one or more wheels or tracks provided in each wheelstation. Furthermore, the amphibian need not be a tricycle (i.e. notlimited to an amphibian having handlebars for steering and/or sitastride seating). Alternatively, for example, the amphibian may take theform of a sit in vehicle or buggy with other steering input (e.g. asteering wheel).

The amphibian 10 can be seen to comprise a front wheel 110, preferablyprovided with a front suspension system (not shown), and two rear wheels120, 120′ again preferably provided with a rear suspension system (notshown). A track or tracks may be used as an alternative to either orboth of the front and rear wheels 110, 120, 120′. At least one wheelretraction system (not shown) that is operable to move the front wheel110 and/or the rear wheels 120, 120′ between a protracted position foruse of the amphibian 10 on land and a retracted position for use of theamphibian 10 on water is preferably included. The amphibian 10 isprovided with a hull 200 with a centre portion 210 and two oppositelydisposed and spaced apart side portions 220. Alternatively, other hullforms may be employed. Each hull portion 210, 220 has a forward enddefining a bow or bow portion 212, 222 and the hull portions 210, 220are preferably fixed relative to one another and form a generally rigidassembly with a generally continuous outer hull surface.

The two side portions 220 extend forwardly beyond the centre portion 210a predefined distance and form a front wheel bay 116. The front wheel110 can be located at least partially within the front wheel bay 116 andthe two side portions 220 can extend forwardly up to or beyond arotation axis 111 of the front wheel 110 when in the protracted landengaging position. In some instances, the two side portions 220 canextend at least partially or generally up to or equal to a front surfaceof the front wheel 110 or, in the alternative, the two side portions 220can extend beyond the front surface of the front wheel 110 when thefront wheel 110 is in the protracted position. The two side portions 220can also extend rearwardly along with the centre portion 210 apredefined distance and form rear wheel bays 126, 126′. The rear wheels120, 120′ can be located at least partially within the rear wheel bays126, 126′ and the two side portions 220 can extend rearwardly along withthe centre portion 210 up to or beyond a rotation axis 122, 122′ of therear wheels 120, 120′ when in the protracted position. In someinstances, the two side portions 220 and centre portion 210 can extendrearwardly at least partially or generally up to or equal to a rearsurface of the rear wheels 120, 120′ or, in the alternative, the twoside portions 220 and centre portion 210 can extend rearwardly beyondthe rear surface of the rear wheels 120, 120′ when the rear wheels 120,120′ are in the protracted position.

As with the first preferred embodiment described above, a conduit 214 isprovided in one or both of the two side portions 220 so as to provide atleast one pathway between the front wheel bay 116 the respective lateralside or sides of the amphibian 10 for fluids (water and/or air) to pass.Again, the or each conduit 214 may take any suitable form, as describedin detail above for the first preferred embodiment. For example, theconduit 214 may be open on the underside in the form of a channel, ormay be at least partially closed (across and/or lengthways of theconduit 214) by the hull 200 or other part of the amphibian 10 so as toform a tunnel. Indeed, the conduit 214 may take the form of a tube (e.g.a discrete part or formed by other parts of the amphibian 10). The crosssection of the conduit 214 may be substantially uniform, or may varyalong its length. More particularly, the cross section of the conduit214 may reduce along its length in the rearward direction 2.Alternatively, the cross section of the conduit 214 may increase alongits length in the rearward direction 2. The entry 215 to the conduit 214may be integrated with either one or more of the bow or bow portions212, 222 of the hull portions 210, 220 or may be a discrete entry (suchas with a discrete tube). Preferably, the entry 215 to the conduit 214is open at and/or to the front wheel bay 116. The exit 216 from theconduit 214 may be an exit (discrete or otherwise) laterally to the sideof the amphibian 10, or may be integrated with either one or both of thehull portions 210, 220. Alternatively, the conduit 214 may continuealong a portion of, or the entire length of, the amphibian 10 exiting atthe rear stern or transom, or into and/or at either or both of rearwheel bays 126, 126′. The or each conduit 214 provides for improvedhydrodynamic performance of the amphibian 10 when on water as theaccumulation of water in the front wheel bay 116 resulting from forwardmotion of the amphibian 10 can travel along the or each conduit 214 aswell as or in place of having to pass under the bow portion 212 of hullportion 210 and on under the hull 200. Further improved hydrodynamicperformance of the amphibian 10 can be achieved by shaping of theconduit, both in terms of its entry 215, exit 216, its path and itscross sectional area along its length. For example, by reducing thecross sectional area along the length of an open channel form of conduit214, water passing along is forced out of the conduit 214 along the openunderside due to its incompressibility, thereby generating lift. Inorder for the amphibian 10 to make the transition from its hull 200being in displacement mode to one where it is planing, the through waterspeed of the amphibian 10 must be increased to achieve the necessaryhydrodynamic lift. The hull 200 and bow portions 212, 222 of the hullportions 210, 220 are key in reducing the drag of the hull 10 andfacilitating the necessary gain in speed of the amphibian through thewater. Once on the plane, the hull 200 provides directional stability.However, the hull 200 may be supplemented with conventional strakes orstrakes as discussed in the applicant's UK Patent No. GB2401833B.

Again, with the two side portions 220 extending forwardly and/orrearwardly beyond the centre portion 210, a hull with desirableflotation and minimum and/or desirable width is provided. Stateddifferently, extension of the side portions 220 to form the front wheelbay 116 and/or the rear wheel bays 126, 126′ provides desirable and/oradequate buoyancy for the amphibian 10 in the water and yet affords forthe amphibian 10 to desirably lean and/or turn during use on the land.

Referring next to FIGS. 5 and 6, a frontal bow section of an amphibianaccording to a further preferred embodiment of the present invention canbe seen. In this further embodiment, the amphibian 10 is provided with ahull 200 with a more rounded and pointed centre portion 210 and twooppositely disposed and spaced apart side portions 220. Indeed, thisdemonstrates what might be considered as an alterative hull form asalluded to in the embodiments described above. Here, the hull 200 may beconsidered to simply comprise a main hull denoted by reference numeral200 provided with a bow 210, and two forward side hull portions 220 eachwith a bow 222. As before, therefore, each hull portion 200, 220 has aforward end defining a bow or bow portion 212, 222 and the hull portions210, 220 are preferably fixed relative to one another and form agenerally rigid assembly with a generally continuous outer hull surface.The two side portions 220 extend forwardly beyond the main or centreportion 210 a predefined distance and form a front wheel bay 116. Thefront wheel 110 can be located at least partially within the front wheelbay 116 and the two side portions 220 can extend forwardly up to orbeyond a rotation axis 111 of the front wheel 110 when in the protractedland engaging position. The two side portions 220 extend at leastpartially towards a front surface of the front wheel 110.

Conduits 214 are provided in or between each of the two side portions220 and the main or centre portion 210 so as to provide one or morepathways between the front wheel bay 116 the respective lateral side orsides of the amphibian 10 for fluids (water and/or air) to pass. Eachconduit 214 is open on the underside in the form of a channel, and thecross section of each conduit 214 varies along its length. Moreparticularly, the cross section of each conduit 214 becomes shallowerbut wider along its length in the rearward direction 2. The entry 215 tothe conduit 214 is integrated with the bow portion 212 of the hullportion 210. The exit 216 of each conduit 214 is a discrete exitlaterally to the side of the amphibian 10. Each conduit 214 provides forimproved hydrodynamic performance of the amphibian 10 when on water asthe accumulation of water in the front wheel bay 116 resulting fromforward motion of the amphibian 10 can travel along each conduit 214 aswell as or in place of having to pass under the bow portion 212 of hullportion 210 and on under the hull 200. Further improved hydrodynamicperformance of the amphibian 10 is achieved by shaping of the conduit,both in terms of its entry 215, exit 216 and its cross sectional areaalong its length. The cross sectional area reduces slightly along thelength of the open channel form of each conduit 214, and so waterpassing along is forced out of each conduit 214 along the open undersidedue to its incompressibility, thereby generating lift.

Referring next to FIG. 7, a further preferred embodiment of the presentinvention can be seen to comprise a two wheeled amphibian 10 that hasdesirable leaning and/or turning capability while in use on the land anddesirable buoyancy and stability while in use on water. This alternativeembodiment is similar to that described above with reference to FIGS. 1to 3, and as such like features denoted by like reference numerals willnot be described further here. Instead, reference is made to thedescription above. In this embodiment, however, the conduit 214 providesa pathway between the front wheel bay 116 and rear wheel bay 126 forfluids (water and/or air) to pass. Alternatively, the conduit could berouted to the rear or transom of the amphibian 10. The conduit 214 (oreach, if plural, or each part if branches of the conduit 214 areprovided) may take any suitable form. For example, the conduit 214 maybe open on the underside in the form of a channel, as shown, or may beat least partially closed (across and/or lengthways of the conduit 214)by the hull 200 or other part of the amphibian 10 so as to form atunnel. Indeed, the conduit 214 may take the form of a tube (e.g. adiscrete part or formed by other parts of the amphibian 10), eitherinside of the lower planing surface of the hull 200, or otherwise. Thecross section of the conduit 214 may be substantially uniform, as shown,or may vary along its length. More particularly, the cross section ofthe conduit 214 may reduce along its length in the rearward direction 2.Alternatively, the cross section of the conduit 214 may increase alongits length in the rearward direction 2. The entry 215 to the conduit 214may be integrated with either one or more of the bow or bow portions212, 222 of the hull portions 210, 220 or may be a discrete entry (suchas with a discrete tube). Preferably, the entry 215 to the conduit 214is open at and/or to the front wheel bay 116. The exit 216 from theconduit 214 may be an exit (discrete or otherwise) laterally to the sideof the amphibian 10, or may be integrated with either one or both of thehull portions 210, 220. Alternatively, the conduit 214 may continuealong a portion of, or the entire length of, the amphibian 10 exiting atthe rear stern or transom, or into and/or at a rear wheel bay 126 (asshown). The or each conduit 214 provides for improved hydrodynamicperformance of the amphibian 10 when on water as the accumulation ofwater in the front wheel bay 116 resulting from forward motion of theamphibian 10 can travel along the or each conduit 214 as well as or inplace of having to pass under the bow portion 212 of hull portion 210and on under the hull 200. Further improved hydrodynamic performance ofthe amphibian 10 can be achieved by shaping of the conduit, both interms of its entry 215, exit 216, its path and its cross sectional areaalong its length.

Referring next to FIG. 8, a further preferred embodiment of the presentinvention can be seen to comprise a three wheeled amphibian 10 that hasdesirable leaning and/or turning capability while in use on the land anddesirable buoyancy and stability while in use on water. This alternativeembodiment is similar to that described above with reference to FIG. 4,and as such like features denoted by like reference numerals will not bedescribed further here. Instead, reference is made to the descriptionabove. In this embodiment, however, the conduit 214 provides a pathwaybetween the front wheel bay 116 and rear wheel bays 126, 126′ for fluids(water and/or air) to pass. The conduit 214, as shown, branches mid-wayand provides two exits, one at each of wheel bays 126, 126′. However,this branching is optional and just one conduit, or multiple discreteconduits, may be provided. Alternatively, the or each conduit (or branchthereof) could be routed to the rear or transom of the amphibian 10. Theconduit 214 (or each, if plural) may take any suitable form. Forexample, the conduit 214 may be open on the underside in the form of achannel, as shown, or may be at least partially closed (across and/orlengthways of the conduit 214) by the hull 200 or other part of theamphibian 10 so as to form a tunnel. Indeed, the conduit 214 may takethe form of a tube or tubes (e.g. a discrete part or formed by otherparts of the amphibian 10), either inside of the lower planing surfaceof the hull 200, or otherwise. The cross section of the conduit 214 maybe vary, as shown, or may be substantially uniform along its length.More particularly, the cross section of the conduit 214 may reduce alongits length in the rearward direction 2. Alternatively, the cross sectionof the conduit 214 may increase along its length in the rearwarddirection 2. The entry 215 to the conduit 214 may be integrated witheither one or more of the bow or bow portions 212, 222 of the hullportions 210, 220 or may be a discrete entry (such as with a discretetube). Preferably, the entry 215 to the conduit 214 is open at and/or tothe front wheel bay 116. The exits 216 from the conduit 214 may be anexit (discrete or otherwise) laterally to the side of the amphibian 10,or may be integrated with either one or both of the hull portions 210,220. Alternatively, the conduit 214 may continue along a portion of, orthe entire length of, the amphibian 10 exiting at the rear stern ortransom, or into and/or at a rear wheel bays 126, 126′ (as shown). Theor each conduit 214 provides for improved hydrodynamic performance ofthe amphibian 10 when on water as the accumulation of water in the frontwheel bay 116 resulting from forward motion of the amphibian 10 cantravel along the or each conduit 214 as well as or in place of having topass under the bow portion 212 of hull portion 210 and on under the hull200. As before, further improved hydrodynamic performance of theamphibian 10 can be achieved by shaping of the conduit, both in terms ofits entry 215, exit 216, its path and its cross sectional area along itslength.

Although the hull 200 has been described as a hull, it is common foramphibians to have a hull, which is a lower water facing/engagingenclosure, and a body, which is an upward enclosure. These may be joinedtogether at a peripheral joint, as disclosed in applicant's co-pendingapplication published as U.S. Application Publication No. 2006/0199499,which is incorporated herein in its entirety by reference. In thealternative, a singular hull can be used which may or may not have alower body with a separate but permanently attached upper body. Such ahull 200 can provide attractive styling for the amphibian, can providesealing of the steering system against water ingress, can providesealing of the at least one wheel retraction system against wateringress, and can provide mountings for desirable equipment such as aninstrument console, a windscreen and the like.

Whilst in certain embodiments the hull has been described as comprisingcentral and side portions, these are only exemplary and other hullconfigurations are possible. For example, the hull may comprise a mainhull with forwardly positioned and laterally spaced apart hull portions.The forwardly positioned and laterally spaced apart hull portions maydefine a front wheel bay. Alternatively, the hull may comprise twolaterally spaced apart hull portions running fore and aft, with a lowerplaning surface at least partially joining the two laterally spacedapart hull portions. Yet further, the hull may comprise one central andtwo laterally spaced apart hull portions running fore and aft, with alower planing surface at least partially joining the centre and twolaterally spaced apart hull portions. The various hull forms may have awheel bay or discontinuity provided at a forward end of the hull.

The term “discontinuity” as used herein includes within its ambit thesimple provision, or forming of, a wheel bay in or on the wet side oroutside of the hull, and is not limited to a discontinuity or otherirregularity in, or through, the surface of the hull. As such, a wheelbay (and in particular each of wheel bays 116, 126 and 126′) is adiscontinuity in the hull.

As used herein, the term “outside” or “wet side” of the hull is a sideor surface of the hull exposed to water, as opposed to the inside of thehull, which is normally substantially dry, being effectively sealedagainst water ingress. Consequently, the front and/or rear wheels 110,120 located in the front and/or rear wheels bays 116, 126, 126′ arelocated on the outside or wet side of the hull in both the protractedand retracted position. It is acknowledged that a conventional enginecompartment requires ingress and egress of air for cooling, combustionand exhaust purposes, but such air intakes and exhaust openings havelabyrynthine passages, commonly known as dorades, in order to exclude asmuch water as possible from the “inside” or “dry side” of the hull. Thatsaid, bilge or other pumps may be provided on the “inside” or “dry side”of the hull to remove unwanted water.

The present invention may further comprise a frame, hull or body form orother structure for supporting one or components or sub-assemblies ofthe amphibian. The front wheel and front suspension system can bemounted to said frame, hull or body form or other structure mounted tosaid frame, and the rear wheel(s) and rear suspension system(s) can alsobe mounted to said frame, hull or body form or other structure mountedto said frame.

Each feature disclosed in this specification (including the accompanyingclaims, abstract and drawings), may be replaced by alternative featuresserving the same, equivalent or similar purpose, unless expressly statedotherwise. Thus, unless expressly stated otherwise, each featuredisclosed is one example only of a generic series of equivalent orsimilar features. In addition, all of the features disclosed in thisspecification (including the accompanying claims, abstract anddrawings), and/or all of the steps of any method or process sodisclosed, may be combined in any combination, except combinations whereat least some of such features and/or steps are mutually exclusive.Accordingly, while different embodiments of the present invention havebeen described above, any one or more or all of the features described,illustrated and/or claimed in the appended claims may be used inisolation or in various combinations in any embodiment. As such, any oneor more feature may be removed, substituted and/or added to any of thefeature combinations described, illustrated and/or claimed. For theavoidance of doubt, any one or more of the features of any embodimentmay be combined and/or used separately in a different embodiment withany other feature or features from any of the embodiments.

The invention is not restricted to the illustrative embodimentsdescribed above. Whereas the present invention has been described inrelation to what is presently considered to be the most practical andpreferred embodiments, it is to be understood that the invention is notlimited to the disclosed arrangements but rather is intended to covervarious modifications and equivalent constructions included within thescope of the appended claims.

The invention claimed is:
 1. An amphibian operable in land and marinemodes, the amphibian comprising: a hull; at least one of a discontinuityprovided in and a discontinuity formed by the hull; and at least one ofa retractable wheel and a retractable track assembly at least partiallylocated in the at least one discontinuity, wherein: the hull is aplaning hull; the at least one discontinuity is provided in a front halfof the hull of the amphibian; and the amphibian further comprises atleast one of a conduit which opens and a conduit provided with an entrywhich at least one of opens into and opens at the at least onediscontinuity and is configured for channelling, in use, fluid away fromthe at least one discontinuity.
 2. The amphibian as claimed in claim 1wherein the at least one conduit is configured for channelling, in use,fluid away from the at least one discontinuity to at least one of aside, along, underneath, inside, and to a rear of the amphibian.
 3. Theamphibian as claimed in claim 1 wherein the at least one conduit isconfigured for channelling, in use, fluid away from the at least onediscontinuity along the underside of the amphibian.
 4. The amphibian asclaimed in claim 1, wherein the at least one conduit is at leastpartially open at a point along a length of the at least one conduit inthe form of a channel.
 5. The amphibian as claimed in claim 1, whereinthe at least one conduit is closed at a point along a length of the atleast one conduit in the form of at least one of a tunnel and a tube. 6.The amphibian as claimed in claim 1, wherein the cross section of the atleast one conduit is substantially uniform along a length of the atleast one conduit.
 7. The amphibian as claimed in claim 1, wherein thecross section of the at least one conduit varies along a length of theat least one conduit.
 8. The amphibian as claimed in claim 7 wherein thecross section of the at least one conduit reduces along the length in adirection downstream from an entry of the at least one conduit.
 9. Theamphibian as claimed in claim 7 wherein the cross section of the atleast one conduit increases along the length in a direction downstreamfrom an entry of the at least one conduit.
 10. The amphibian as claimedin claim 1, wherein the at least one conduit is formed in an undersideof the hull.
 11. The amphibian as claimed in claim 1, wherein the atleast one conduit is a discrete part of the amphibian separate from thehull.
 12. The amphibian as claimed in claim 1, wherein the at least oneconduit is formed, at least in part, inside of an underside of the hull.13. The amphibian as claimed in claim 1, wherein the at least oneconduit has an exit for fluid at any one or more of a side and an end ofthe at least one conduit of a length of the at least one conduit length.14. The amphibian as claimed in claim 1, wherein the at least oneconduit channels, in use, water which accumulates in the at least onediscontinuity resulting from forward motion of the amphibian when atleast one of in and on water in marine mode.
 15. The amphibian asclaimed in claim 14 wherein: the at least one conduit is formed in anunderside of the hull and is partially open at a point along a length ofthe at least one conduit in the form of a channel in the underside ofthe hull; and the cross section of the at least one conduit reducesalong the length of the at least one conduit in a direction downstreamfrom an entry of the at least one conduit, wherein: in use, waterpassing along the at least one conduit is forced out of the conduitalong the open underside thereby generating lift.
 16. The amphibian asclaimed in claim 1, wherein the at least one discontinuity provided inthe hull comprises a front wheel bay.
 17. The amphibian as claimed inclaim 1, wherein the at least one discontinuity provided in the hullcomprises a single front wheel bay.
 18. The amphibian as claimed inclaim 1, wherein the at least one discontinuity provided in the hullcomprises a front wheel bay formed on the outside of the hull.
 19. Theamphibian as claimed in claim 16, wherein the hull extends between a bowand a stern/transom, the bow having a central bow portion and a pair ofside bow portions, the central bow portion being disposed rearwardly ofthe side bow portions so as to define the front wheel bay.
 20. Theamphibian as claimed in claim 1, wherein at least one of a wheel and atrack of the at least one retractable wheel and retractable trackassembly is retracted above a lowest point of the hull when operating inmarine mode, and at least part of the at least one of the wheel andtrack is protracted below the lowest point of the hull when operating inland mode.
 21. The amphibian as claimed in claim 1, further comprising:a land propulsion unit to propel the amphibian on land in the land mode,the land propulsion unit comprising at least one of the wheel and thetrack; and a marine propulsion unit to propel the amphibian on water inthe marine mode.
 22. The amphibian as claimed in claim 21 wherein themarine propulsion unit comprises at least one of jet drives andpropellers.
 23. The amphibian as claimed in claim 22 wherein the atleast one of jet drives and propellers can propel the amphibian to aspeed where sufficient hydrodynamic lift is generated to enable theamphibian to plane.
 24. The amphibian as claimed in claim 1, wherein theamphibian is an amphibian motorcycle having at least one of a frontwheel and track and at least one of a rear wheel and track.
 25. Theamphibian as claimed in claim 1, wherein the amphibian is an amphibianmotorcycle having at least one of a front wheel and track station and atleast one of a rear wheel and track station.
 26. The amphibian asclaimed in claim 1, wherein the amphibian is an amphibian tricyclehaving at least one of a front wheel and track in a front half of theamphibian and at least one of two rear wheels and tracks in a rear halfof the amphibian.
 27. The amphibian as claimed in claim 1, wherein theamphibian is an amphibian tricycle having at least one of a front wheeland track station in a front half of the amphibian and at least one oftwo rear wheel and track stations in a rear half of the amphibian. 28.The amphibian as claimed in claim 25, wherein the amphibian comprises atleast one of one or more wheels and tracks in at least one of the frontwheel and track station and the rear wheel and track stations.
 29. Theamphibian as claimed in claim 1, wherein the amphibian comprises asit-in amphibian having at least one of a front wheel and track in afront half of the amphibian and at least one of a rear wheel and trackin a rear half of the amphibian.
 30. The amphibian as claimed in claim1, wherein the amphibian comprises a sit-in amphibian having at leastone of a front wheel and track in a front half of the amphibian and atleast one of at least two rear wheels and tracks in a rear half of theamphibian.
 31. The amphibian as claimed in claim 1, wherein theamphibian comprises a sit-in amphibian having at least one of a frontwheel and track station in a front half of the amphibian and at leastone of a rear wheel and track station in a rear half of the amphibian.32. The amphibian as claimed in claim 1, wherein the amphibian is asit-in amphibian having at least one of a front wheel and track stationin a front half of the amphibian and at least one of at least two rearwheel and track stations in a rear half of the amphibian.
 33. Theamphibian as claimed in claim 1, wherein the amphibian has a steeringinput for use by a rider or driver.
 34. The amphibian operable in landand marine modes, the amphibian comprising: a hull; at least one of awheel bay and a track bay provided in, or formed by, the hull; and atleast one of a retractable wheel and a retractable track assembly atleast partially located in the at least one of the wheel bay and thetrack bay, wherein: the hull is a planing hull; the at least one of thewheel bay and the track bay is provided in a front half of the hull ofthe amphibian; and the amphibian further comprises at least one of aconduit which opens and a conduit provided with an entry which at leastone of opens into and opens at the at least one of the wheel bay and thetrack bay and is configured for channelling, in use, fluid away from theat least one wheel or track bay.